For those performing repairs or deep diagnostics, the battery contains internal contact points (often labeled ) used by the charger to balance the five individual 4V lithium-ion cells. C1: ~4V (relative to Negative) C2: ~8V C3: ~12V C4: ~16V Safety & Maintenance Tips
| Brand | Terminals | ID Method | Cross-Compatible? | |-------|-----------|-----------|-------------------| | | 5 (B-, T2, T1, ID, B+) | 1-Wire serial (TTI proprietary) | No (with Ryobi/Milwaukee) | | Ryobi 18V | 6 (B-, T1, T2, ID, B+, HS) | Analog resistor (different Ω per Ah) | No – Physical slot different | | Milwaukee M18 | 7 (B-, T, C, B+, 3 balance) | Digital handshake + temperature | No | | DeWalt 20V | 4 (B-, C, TH, B+) | Single-wire proprietary (TD) | No | Hart 20v Battery Pinout Diagram
The battery and charger use these pin connections to signal specific faults, such as "Temperature Out of Range" or "Over Current Detected," usually through flashing lights on the charger or battery fuel gauge. to build a DIY adapter troubleshoot a battery that isn't charging? Hart 20v Battery Pinout Wiring Diagram For those performing repairs or deep diagnostics, the